Seeing the names of two of radical feminism's most famous activists pop out in the closing credits of Lovelace might have surprised filmgoers over the weekend. The biopic about the star of the notorious 1972 porn film Deep Throat came with help from Catharine MacKinnon, a lawyer and anti-pornography campaigner, and Gloria Steinem, founder of Ms magazine.

The pair met Linda "Lovelace" Marchiano just before she released her (third) memoir, Ordeal, in 1980. In it, she wrote of being abused, pimped and raped by her then husband Chuck Traynor who reportedly forced her to make Deep Throat at gunpoint. The three of them worked as anti-porn campaigners for the next two decades and MacKinnon became Linda's lawyer. MacKinnon has represented Linda's children and estate since the actor-turned-activist died in 2002, so when producers wanted to make a film about her life story they went to her for permission.

"Our fear was that [the film] would just be more sexual exploitation of Linda," says MacKinnon. "But after meeting the producers and directors, we were clear that they wanted to do right by Linda," and would help "viewers experience the core truth of what happened to [her], and to view pornography in general in a more critical light." Steinem – who also consulted on the movie, particularly on the casting of Amanda Seyfreid as Lovelace – wanted audiences "to connect Linda's experiences to the experiences of thousands of women who, as we speak, are being conned by pimps and being imprisoned in the same way".

For Steinem, the fight against pornography has never been more urgent. "We have, on the one hand, a religious right wing that is suppressing anything that might be called sex education and a huge growth in pornography on the other. Pornography is becoming the only form of sex education."

Initially, the movie included a scene at Ms magazine, in which Sarah Jessica Parker plays Steinem, but it ended up on the cutting room floor when film-makers decided that Marchiano's activist work could make a whole other movie ("and it should!" says Steinem). Still, Steinem and MacKinnon seem satisfied with the role they played when the cameras were not rolling. Though reviews have been mixed and some anti-pornography campaigners have complained that the film is too kind in its portrayal of the makers of Deep Throat, they say Lovelace's real success has been in raising awareness of Marchiano's story.

Many doubted her version of events when Ordeal was published; many still do now. And yet "Ordeal is now back-ordered by three or four weeks at Amazon," says MacKinnon.

"The deepest thing I felt while watching the movie – though it couldn't show the whole truth about her gang rape and internal injuries, and then years of being disbelieved and ridiculed – the thing that brought tears to my eyes," says Steinem, "was that Linda would have felt that her true story was more present in the world." MacKinnon adds: "I felt a combination of deep sadness that this level of respect was something Linda never saw in her lifetime, and joy and triumph that her victory is out there for the people who surround her children to see."